Alkylated cyclopentadienyl manganese tricarbonyls are antiknock additives, with methyl cyclopentadienyl manganese tricarbonyl (MMT) being the most widely used. Registered Chinese Patent No. 97122153 discloses a method for producing cyclopentadienyl manganese tricarbonyl. However, the cyclopentadienyl manganese tricarbonyl produced by that method is a crystalline salt. The use of a crystalline salt as an antiknock additive in a liquid poses certain problems. Its dissolution in the solvent is a problem which must be solved in the process.
Furthermore, during the course of producing alkylated cyclopentadienyl manganese tricarbonyl, it is often unavoidable to generate by-products such as cyclopentadienyl manganese tricarbonyl (CMT). Removing the CMT by-product requires further equipment and expense. However, the method of producing alkylated cyclopentadienyl manganese tricarbonyl involved in the current invention is characterized in that it does not require the removal of the CMT by-product. A small quantity of CMT in a mixture with alkylated cyclopentadienyl manganese tricarbonyl produces an unexpected octane synergism.